Question
Question (6 marks): A student calculated rₛ = +0.74 (n = 12) for the relationship between distance from CBD and house price in Cardiff. Critical values: 0.591 (0.05), 0.777 (0.01). Explain what this result means and how it should be reported.
Mark scheme (levelled, 6 marks):
- Level 1 (1–2): States the relationship is positive or strong without statistical reasoning.
- Level 2 (3–4): Identifies that 0.74 > 0.591 so the result is significant at the 0.05 level; H₀ (no relationship) is rejected. Recognises it does not exceed 0.777 so cannot claim 99% confidence.
- Level 3 (5–6): Full statistical literacy — states the alternative hypothesis, notes that correlation does not imply causation, comments on sample size (n = 12 is small), and acknowledges that confounding variables (e.g. school catchment) may drive the pattern. Uses precise language: "significant at the 5% level", not "proven".
6 marks · take your time before peeking.
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Generated by TopMyGrade AI · cross-check official sources before relying on the mark-scheme phrasing.